Hello Sandip,
I can think of 2 options on top of mind , check if any of them useful for you
1. Change user exit - EXIT_SAPLL03A_013 (Include - ZXLTOU19) to include/exclude the check
2. Create different movement type in IM (copy of 601) assign it to STO's and create copy of WM movement type and map them.
Hope this helps,
Nag